The social-media sensation that is the ALS Ice Bucket Challenge took a disastrous, tragic turn on Thursday when two Campbellsville, Ky. firefighters were seriously injured at the conclusion of an event during which they doused freezing cold water on a college marching band.

As of late Thursday night, Grider remained in critical condition. Quinn, a part-time member of the fire department, was listed in fair condition.

Two more firefighters received shocks but were not badly hurt. They received treatment at a local hospital and were released.

The four firefighters had gone in an aerial ladder truck to the 3,600-student Baptist-affiliated school — located just across the street from the firehouse — to take part in an Ice Bucket Challenge fundraiser for the fight against amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease), a neurodegenerative disease that slowly devastates the muscles of its victims.

The accident happened as the two gravely injured firefighters were lowering the fire truck bucket and it came too near a high-voltage power line.

Allen Johnson, previously chief of the Campbellsville fire department and the father of one of the two firefighters who suffered minor injuries, elaborated on the danger of power arcs.

“That voltage will jump feet. Not inches — feet,” Johnson told the Herald-Leader, adding that the power line that caused the injuries conducted 69,000 volts.

“The job that we do is dangerous,” the former chief added. “I hope it never happens, nowhere, to a firefighter again.”

The accident had other effects as well, knocking out power in parts of the surrounding county and a neighboring county for a little over an hour. Many landline phones were also affected.

Campbellsville University President Michael V. Carter released a statement expressing “heartfelt sympathy and prayers for the families of the two firefighters who were injured.”

Hundreds of students and local residents attended a prayer vigil on campus on Thursday night.

“They’re heroes, What they do is completely heroic,” a Campbellsville University student told local CBS affiliate WKYT. “They put their life on the line every day. It was a simple day, just helping some of the band students do an ALS water challenge and God had a different plan.”